DE2623333C2 - Process for the preparation of arylene sulfide polymers - Google Patents

Description

R '

C = O

R "

40

wherein each R 'is hydrogen or R "and R" is an alkyl radical having 1 to 3 carbon atoms, where the total number of carbon atoms in each N-alkyl-2-pyrrolidone is 5 to 8 ^, and with lithium acetate, characterized in that before the introduction of the p-dihalobenzene or the polyhalogenated aromatic compound in the Reaction zone the other starting materials are freed from water as follows:

(a) Prepare a first composition by mixing N-alkyl-2-pyrrolidone, lithium acetate and free water or water of hydration;

(b) dehydrating this first composition to form a first one. d-nj'dratized Composition;

(c) mixing the first dehydrated composition with a second Zusammenset · m pollution, which contains at least 50 wt .-% of free water or water of hydration and a AlMisulfid to a third composition and

(d) dehydrating the third composition to a third dehydrated composition, r> Settlement to which the p-dihalobenzene ui.il optionally the polyhalogenated aromatic compound can be added.

2. The method according to claim 1, characterized in that that the second composition additionally as a base an alkali hydroxide and / or an alkali carbonate contains.

3. The method according to claim 1 or 2, characterized in that the dehydration by evaporation of the water is carried out.

4. The method according to any one of the preceding claims, characterized in that the p-dihalobenzene is p-dichlorobenzene

5. The method according to any one of the preceding claims, characterized in that the reaction mixture contains 1,2,4-trichlorobenzene as a polyhalogenated aromatic compound.

The invention relates to a process for the preparation of arylene sulfide polymers of higher value Molecular weight.

The production of arylene sulfide polymers of higher molecular weight, such as this through a lower one Value for the melt flow, without curing the polymer, is expressed as compared to known arylene sulfide polymers of particular interest, since arylene sulfide polymers with lower Melt flow, in particular with melt flow values in the range from 1 to 700, determined according to ASTM D 1238-70, are particularly useful for the production of fibers, moldings and filaments, since the usual No hardening stage.

When preparing an arylene sulfide polymer using p-dihalobenzene, alkali sulfide, Liihiumacetat and N-alkyl-2-pyrrolidone and optionally a polyhalogenated aromatic compound with more than two halogen substituents in the molecule, the lithium acetate is generally as a dihydrate and the alkali sulfide is generally as Hydrate and / or used as a mixture with free water. For example, it is convenient to use the alkali sulfide in the form of a composition containing 45 to 50% by weight sodium sulfide, expressed as Na ₂ S, this composition being made from aqueous sodium hydroxide and aqueous sodium bisulfide, both of which are commercially available are available. However, it is advantageous to use the water from both the lithium acetate as well as from the present in hydrated form / or in and mixing with celebrate water alkali metal sulfide to be removed, before the p-Dihalohenzol and optionally ve ^r turned polyhalogenated aromatic compound having more than two halogen substituents in the molecule are brought into contact with each other with the other starting materials that are used to manufacture the polymer. Although the water from the mixture of lithium acetate dihydrate and the hydrated and / or mixed with free water alkali metal sulfide can be removed into an N-alkyl-2-pyrrolidone by distillation in a one-stage dehydration, it is disadvantageous to proceed in this way because the arylene sulfide polymers prepared in this manner have relatively high melt flow values.

It is therefore an object of the invention to provide arylene sulfide polymers of higher molecular weight and lower To provide melt flow values.

The invention therefore provides a method for producing an arylene sulfide polymer by

Reacting a p-dihalobenzene of the general formula

10

in which each X is chlorine, bromine or iodine and each R is hydrogen or an alkyl, cycloalkyl or aryl radical or a combination thereof, the total number of carbon atoms in each molecule being in the range from 6 to 24, with the restriction that in at least 50 mol% of the p-dihalobenzene used, each R is hydrogen, optionally together with up to 0.6 parts by weight per 100 parts by weight of p-dihalobenzene, at least one polyhalogenated aromatic compound having more than two halo substituents in the molecule of the formula R '" X ", in which X has the meaning already defined, η is an integer from 3 to 6, and R '" is a polyvalent aromatic radical of valence π , which can have up to 4 methyl substituents, the total number of carbon atoms in R '"is in the range from 6 to 16, with an alkali sulfide in the presence of an N-alkyl-2-pyrrolidone of the formula

-R '

C = O

R "

20th

30th

35

in which each R 'is hydrogen or R "and R" is an alkyl radical having 1 to 3 carbon atoms, the total number of carbon atoms in each N-alkyl-2-pyrrolidone 5 to 8 and with lithium acetate. The method is characterized in that before introducing the p-dihalobenzene or the polyhalogenated aromatic compound into the reaction zone the other raw materials are freed from water as follows:

(a) Prepare a first composition by mixing N-alkyl-2-pyrrolidone, lithium acetate and free water or water of hydration;

(b) dehydrating this first composition to form a first dehydrated composition;

(c) mixing the first dehydrated composition with a second composition which contains at least 50% by weight of free water or water of hydration and an alkali metal sulfide, to a third Composition and

(d) dehydrating the third composition to a third dehydrated composition, to which the p-dihalobenzene and optionally the polyhalogenated aromatic compound be admitted.

Surprisingly, this two-stage dehydration gives arylene sulfide polymer of μ higher molecular weight and lower melt nut values than in the known one-step dehydration.

In a preferred embodiment of the invention, the second composition also contains one Base from the group of alkali hydroxides and alkali carbonates.

The optionally used polyhalogenated aromatic Compounds with more than two halogen substituents in the molecule can be essentially the same Time as the p-dihalobenzene is added. But you can also use them in part or in one piece add during the course of the polymerization or after the start of the polymerization.

The two-stage dehydration also leads to one compared to a one-stage dehydration less foaming and flooding of the distillation column and yields arylene sulfide polymers of higher molecular weight, which is due to the lower melt flow value and higher inherent viscosity If the starting material is not only p-dihalobenzene, but also at least one polyhalogenated aromatic compound with more than two halo substituents in the molecule is used resulting polymers a branched arylene sulfide polymer. If, however, without the addition of a polyhalogenated aromatic compound with more than two halogen substituents is worked, a linear arylene sulfide polymer, for example a linear p-phenylene sulfide polymer.

Examples of suitable p-dihalobenzenes are

p-dichlorobenzene,

p-dibromobenzene,

p-diiodobenzene,

l-chloro-4-bromobenzene,

l-chloro-4-iodobenzene,

l-bromo-4-iodobenzene,

2,5-dichlorotoluoi,

2,5-dichloro-p-xylene,

l-ethyl-4-isopropyl-2,5-dibromobenzene,

l-butyl-4-cyclohexyl-2,5-dibrornobenzoi,

l-Hexyl-S-dodecyl ^^ - dichlorobenzene.

1-octadecyl ^^ - diiodobenzene,

l-phenyl ^ -chloro-S-bromobenzene,

1 -p-Tolyl ^^ - dibromobenzene,

1 -Benzyl ^^ - dichlorobenzene,

1-octyl-4- (3-methylcyclopentyl) -2,5-dichlorobenzene and mixtures thereof.

Examples of combined hydrocarbons containing the p-dihalobenzenes as R substituents are alkaryl and aralkyl radicals.

Suitable polyhalogenated aromatic compounds with more than two halogen substituents in the molecule are in the invention for example

1,2,3-trichlorobenzene,

1,2,4-trichlorobenzene,

1, S-dichloro-S-bromobenzene,

1,2,4-triiodobenzene,

1,2-dibromo-4-iodobenzene,

2,4,6-trichlorotoluene,

1,2,3,5-tetrabromobenzene,

Hexachlorobenzene,

2,2 ', 4,4'-tetrachiorbiphenyi,
2,2 ', 5,5'-tetraiodobiphenyl,
2,2 ', 6,6'-tetrabromo-3,3', 5,5'-tetramethylbiphenyl,
1.2.3.4-tetrachloride-ththalene.

1 ^^ - tribromo-o-roethylnaphthalene and
Mixtures thereof.

The alkali sulfides used in the process according to the invention are lithium sulfide, sodium sulfide, potassium sulfide. Rubidium sulfide, cesium sulfide and mixtures thereof are contemplated. The alkali sulfide can be used in hydrated form and / or as an aqueous mixture. If necessary, the composition containing the alkali sulfide can be obtained by mixing a viüSfki-'i solution of alkali bisulfide, for example aqueous sodium bisulfide, and an aqueous alkali hydroxide, for example aqueous sodium hydroxide.

As already stated, the composition of the alkali bisulfide preferably also contains a base from the group of alkali hydroxides and alkali carbonates. Examples of such bases are lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, Cesium hydroxide, lithium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, cesium carbonate and mixtures thereof.

Examples of some suitable N-alkyl-2-pyrrolidones Door are the method of the invention

N-methyl-2-pyrrolidone,
N-ethyl-2-pyrrolidone,
N-propyl-2-py ι rolidon,
N-isopropyl-2-pyrrolidone,
NOAS-TetramethyW-pyrrolidon,
NO-dimethyl-S-ethyl ^ -pyrrolidone,
N-methyl-S-propyl ^ -pyrrolidone,
N-MethyW-isopropyl ^ -pyrrolidone and
Mixtures thereof.

The molar ratio of p-dihalobenzene to alkali metal sulfide can vary within a considerable range, but the range from 0.9: 1 to 2: 1, preferably 0.95: 1 to 1.2: 1, is generally used. The amount of any polyhalogenated aromatic compound used with more than two halogen substituents per molecule can vary considerably depending on the halogen content of this polyhalogenated aromatic compound, but in general up to 0.6 parts by weight, preferably 0.1 bf ι 0, 4 parts by weight of this compound used for 100 parts by weight of p-dihalobenzene. The molar ratio of lithium acetate to alkali metal sulfide can also vary within a wide range, if a. ^s he generally in the range of from 0.7: 1 to 4: 1, preferably 0.9: 1 to 1.5: 1. If an alkali hydroxide or alkali carbonate is used as the base, their ratio to the alkali sulfide can vary considerably, but the molar ratio is generally up to 0.5: 1, preferably in the range from 0.01: 1 to 0.6: 1. The base that may be used to convert the alkali metal bisulphide has not been taken into account in these figures. The amount of N-alkyl-2-pyrrolidone present during the dehydrations can vary widely, but is generally in the range from 200 g to 1000 g, preferably 300 to 800 g, per gram-mole of alkali metal sulfide used in the polymerization reaction . Optionally, an additional amount of N-alkyl-2-pyrrolidone can be used, for example an amount of up to 1000 g per gram-mole of alkali metal sulfide used, this amount being added after the Dp hydration stages but before the polymerization stage.

The polymafization stone peioture can vary within wide limits. HeKi alier in the alliUMnemen between 125 and 4.1O ¹³ C, bcvüttugi i / 5 to 350 ° Γ. The reaction time can also vary greatly depending on the reaction temperature, but is generally in the range from 10 minutes to 72 hours, preferably 1 to 8 hours. The pressure should be sufficient to keep the p-dihalobenzene, the optionally used polyhalogenated aromatic compound having more than two halogen substituents per molecule, and the urganic amide, essentially in the nutty phase.

The arylene sulfide polymers obtained in the process according to the invention can be obtained from the reaction mixture be separated off by conventional procedures, for example by filtering off the polymer with subsequent washing with water or by diluting the reaction mixture with water and then Filter and wash the polymer with water. Alternatively, one can use the N-alkyl-2-pyrrolidorr remove by distillation from the reaction mixture before washing with water said procedure is used and in the polymerization reactor a larger amount of alkali hydroxide was used as is required for the conversion of the alibisulphide to alkali sulphide, and that N-alkyl-2-pyrrolidone is distilled at elevated temperatures, for example above 200 ° C preferably carbon dioxide during the polymerization reaction or after the end of the polymerization reaction, but before the distillation of the N-alkyl-2-pyrrolidone added to prevent decomposition of the arylene sulfide polymer during distillation of the N-alkyl-2-pyrrolidone to avoid.

The arylene sulfide polymers produced with the aid of the process according to the invention can be scrapped in the customary manner with fillers, pigments, extenders or other polymers. They can be hardened by crosslinking or chain extension, for example by heating to temperatures of up to 480 ^° C. in the presence of gases which contain free oxygen. Cured products of high heat resistance and good chemical resistance are obtained. The arylene sulfide polymers are for the

Suitable for the production of coatings, films, moldings and fibers. Those arylene sulfide polymers which have relatively low melt flow values, for example within a range of 50 to 700 (determined according to ASTM D 1238-70, modified for a temperature of 316 ° C using a 5 kg weight, where the values are given as g / 10 min) are especially for the production of fibers, Moldings and films are suitable, since the otherwise usual cooling stage is not required.

In the following examples, the melt flow values are determined by the method given above. The values for the inherent viscosity were determined at 206 ^° C. in 1-chloronaphthalene at a polymer concentration of 0.4 g / 100 ml of solution.

The invention is explained in more detail in the following comparative experiments and examples.

Comparative experiment 1

The starting materials were used for a comparative experiment dehydrated in filier single stage, taking water ir Forri of free water and as Hyciidiwassc; vnr> sodium sulfide used in a total amount

which roughly corresponded to that used in an industrial manufacture in which aqueous sodium sulfide is made from commercially available sodium bisulfide and aqueous sodium hydroxide.

983.7 g (60% strength, 7.56 mol) sodium sulfide, 46.8 g (1.17 mol) sodium hydroxide, 765 g (7.50 mol) lithium acetate dihydrate, .184.9 g deionized water and 3000 ml (3078 g) N-methyl-2-pyrrolidone was placed in a 7.6 liter reactor equipped with a stirrer, which was then purged with nitrogen. The mixture was made using an electrical heating source with two voltage regulated heating units connected to a 220 volt source. dehydrated. As soon as the mixture reached a temperature of 129 ° C , refluxing was observed and it was necessary to cool the reactor to avoid foaming and flooding of the distillation column. This was the most violent foaming and flooding the Desiiiiaiionskolonne, reached as the pot temperature 143 ⁰ C:..>'at this time 200 ml of distillate had been erhallen the water cooling was continued, and some flooding of the column was observed untilTue pot temperature reached 154 ⁰ C . at that time, 450 m! distillate present. Ks j> was then the water cooling is interrupted, and the distillation was continued until the pot temperature 207 ⁰ C UNJ the distillation temperature reached 183 ° C. the entire distillate consisting mainly Water, had a volume of 1000 ml. 1137 g (7.73 mol) of p-dichlorobenzene and 500 ml (513 g) of N-methyl-2-pvrrolidone were added to the remaining mixture enter. The obtained mixture was heated atm for three hours 266 ⁰ C at a maximum of 12.6 Dm.k. The Reakiicv ^ prudiA! was cooled, washed four times with water, and dried in a vacuum oven to give 658.6 g of poly (p-phenylene sulfide) having a melt flow index of 384 and an inherent viscosity of 0.25.

Example;

In this experiment, the dehydration took place Starting materials in two separate stages! ". ·> became poly (p-phenylene sulfide) using water in free form and as water of hydration in equal ^ Quantities as prepared in comparative experiment 1..

765 g (7.50 Mol> Lithium acetate and 3000 ml (3078 g) N-methyl-2-pyrrolidone 7.6-liter Redktor were in a flask equipped with a stirrer. The reactor was purged with nitrogen. The mixture v · was Unur using the same and equal to the set heat source was dehydrated as in Comparative experiment 1. the heating and the distillation continued until the pot temperature reached 204 ⁰ C, with no foaming or flooding of =, =, column observed.

250 ml of distillate were obtained, which mainly consisted of water. The reactor was then cooled to 93 ° C. while purging with nitrogen. Then 983.7 g (60% pure material, 7.56 mol) of sodium sulfide were _b o, 46.8 g (iP mol) of sodium hydroxide and 384.9 g deionized water was added. The reactor was purged with nitrogen, and there was a second Dehy performed dratisierungsstufe This second dehydration step was carried supplying heat by an electric heater accomplished Once the pot temperature reached 132 ° C, was cooled with water, mskolonne by a very small flooding the Destilhi to prevent. However, such flooding ceased as soon as the pot temperature had reached 149 ° C. From this point on, the cooling with water was no longer continued. The distillate obtained at this point had a volume of 100 ml and consisted mainly of water. The flooding of the column during this second Destillationsst'ife was very low compared to that of the distillation stage in Comparative Example I. The dehydration was continued, was said to observe a flooding without cooling with water until the pot temperature 209 ⁰ C and the distillation temperature 183 ° C reached. The total distillate, which consisted mainly of water, had a volume of 735 ml. To the remaining mixture were added 1137 g (7.73 mol) of p-dichlorobenzene and 500 ml (513 g) of N-methyl-2-pyrrolidone . The mixture obtained was heated to 266 ° C. for 3 hours at a maximum diut_k nji * i I 2.6 dim gCgCuCfi. The product was refrigerated, washed four times with washer and dried in a vacuum oven. 668.5 g of poly (p-phenylene sulfide) with a melt flow value of 185 and an inherent viscosity of 0.31 were obtained from what results from the values for the melt flow and the inherent viscosity.

Comparative experiment 2

In this comparison experiment, a branched Poly (p-phenylene sulfide) produced by a process which is outside the invention. Water was presented in free form and as 1 hydration water: sodium sulfide in a whole multitude ver ^ er ^ et that of those Amount corresponds to that in industrial production using aqueous sodium sulphate fid, made from commercially available sodium bisulfite and aqueous sodium hydroxide, is used would.

983.7 g (60% product. 7.56 mol) sodium sulfide, 46.8 t (1.17 mol) sodium hydroxide, 765 g (7.50 mol) lithium acetate dihydrate, 384.9 g deionized water and 3000 ml (3078 g) N-methyl 2-pyrrolidone was added to a 7.6 liter reactor equipped with a stirrer, which was then purged with nitrogen. The mixture was then dehydrated by applying heat from an electric heater during the dehydration step. As soon as the mixture had reached a temperature of 134 ° C, boiling and refluxing began, and ·. water cooling of the reactor was necessary up · foaming and flooding of the distillation column to control. The vigorous foaming and flooding stopped as soon as the pot temperature reached 141 ° C. At this point in time, 275 ml of distillate had formed. It was then water cooling unterbro chen, and the distillation was continued until the pot temperature 206 ⁰ C and the distillation temperature reached 183 ° C. The entire distillate, which consisted primarily of water, a volume of 1250 ml was. Were 1137 g (7.73 mol) of p-dichlorobenzene, to the rest of the mixture 1.5 g (0.0083 mol) and trichlorobenzene 1,2.4- 500 ml (513 g) of N-methyl-2-pyrrolidone were added. The resulting mixture was heated to 266 ° C at a maximum pressure of 12.6 atm for three hours. The reaction product was cooled, washed four times with water and in one

Vacuum oven dried. There were 613.3 g of a branched Poly (p-phenylene sulfide) having a Melt Rating of 572 and an inherent viscosity of 0.19 received

Example 2

In this experiment, a branched polyphenolsulfide) according to the invention using water in free form and as water of hydration produced in the same quantities as in comparative experiment 2.

765 g (7.50 mol) of lithium acetate dihydrate and 3000 ml (3078 g) of N-methyl-2-pyrrolidone were placed in a 7.6 liter reactor equipped with a stirrer, and the reactor was purged with nitrogen. The mixture was then dehydrated by applying heat during the dehydration step by the same electrical means as in Comparative Experiment 2. The heating and distillation were continued until the Topf'temperatur reached 204 ⁰ C, with no foaming or flooding of the column was observed. It was 310 m! Obtained distillate, which consisted mainly of water. The reactor was then cooled to 93 ° C while purging with nitrogen. 983.7 g (60% strength product, 7.56 mol) of sodium sulfide, 46.8 g (1. 17 mol) of sodium hydroxide and 384.9 g of deionized water were then added. The reactor was then purged with nitrogen and a second stage of dehydration was carried out. The same electric heater was used for this second step of dehydration as that used for the first step. The dehydration was carried out without flooding the column and without water cooling until the pot temperature 206 ⁰ C and thee distillation temperature reached 183 ° C. The entire distillate, which consisted primarily of water, had a volume of 950 ml. 1137 g (7.73 mol) of p-dichlorobenzene, 1.5 g (0.0083 mol) of 1,2,4- Trichlorobenzene and 500 ml (513 g) N-methyl-2-pyrrolidone added. The resulting mixture was heated to 266 ° C. at a maximum pressure of 12.9 atm for three hours. The reaction mixture was cooled, washed four times with water, and dried in the vacuum oven. 688.6 g of a branched poly (p-phenylene sulfide) having a melt flow value of 148 and an inherent viscosity of 0.26 were obtained.

As a result, this example also confirms that there is no foaming and flooding upon dehydration of the column as in Comparative Experiment 2 occurred. In addition, the molecular weight is also in this example of branched poly (p-phenylene sulfide) is significantly higher than in comparative experiment 2.

Claims (1)

Patent claims: 1. Process for producing an arylene sulfide polymer by reacting a p-dihalobenzene of the general form! in in which each X is chlorine, bromine or iodine and each R is hydrogen or an alkyl, cycloalkyl or aryl radical or a combination thereof, the total number of carbon atoms in each molecule being in the range of 6 to 24, with the restriction that with at least 50 mol% of the p-dihalobenzene used, each R is hydrogen, optionally together with up to 0.6 parts by weight per 100 parts by weight of p-dihalobenzene at least one polyhalogenated aromatic compound with more than two halogen substituents in the molecule of the formula R '"X ", In which X has the meaning already defined, η is an integer from 3 to 6 and R '" is a polyvalent aromatic radical of valence π , which can have up to 4 methyl substituents, the total number of carbon atoms in R'"is in the range from 6 to 16, with an alkali sulfide in the presence of an N-alkyl-2-pyrrolidone of the general formula